See for example this: https://forum.airgradient.com/t/airgradient-diy-pro-pcb-3-7-..., linked to a Github issue opened in June.
Somehow, the source code for the new version has been overwritten by an older (CC-BY-NC) version, yet the issue has been left to rot, both on the support forum and on Github, letting me to think that the "openness" is mostly a posture to lure the HN crowd. Additionally, the -NC clause is definitely a deal breaker, and I should have investigated further before giving them my money.
(it sucks to air it out in public here, but apparently the AirGradient folks don't care much about issues raised on their own forum).